NPL Environmental Radioactivity Comparison 2005

Results from LNGS

NPL Environmental Radioactivity Comparison 2005

The LNGS LBL has participated (not formally) to a comparison exercise promoted by NPL (National Physical Laboratory, UK)

SAMPLE:

Type GL: sample consists of 500 g of 2 M HCl/0.1 M oxalic acid with 50 ppm of Ba, Co, Na, Nb, Sb, Y and Zr, containing a mixture of ten gamma-emitting radionuclides:

22Na, 60Co, 88Y, 95Zr, 95Nb, 125Sb, 133Ba, 134Cs, 137Cs, 152Eu

The activity concentration of each nuclide was in the range 1-20 Bq/kg.

Nuclide 22Na 60Co 88Y 95Zr 95Nb 125Sb 133Ba 134Cs 137Cs 152Eu

Activity

[Bq/kg]3.718 (14)

18.84 (6) 3.843 (14) 1.836 (19) 3.84 (4) 6.48 (4) 5.74 (4) 5.30 (4) 2.884 (20) 4.19 (3)

Reference time: October 1, 2005

Results

-40

-20

0

20

40

60

80

100

120

Dev

iati

on

[%

]

22Na 60Co 88Y 95Zr 95Nb 125Sb 133Ba 134Cs 137Cs 152Eu

Measurement: GeMi Detector 124.5 g volume: d70mm h40mm measuring time 92.6 h

Deviation from NPL reference results:

D[%] = 100*(Meas/Ref-1)

Mean Value-2.84%

Conclusions

Problems with 95Nb: 95Zr 95Nb or 95mNb 95mNb 95Nb or 95Mo 95Nb 95Mo